Ultrasonic Weld Force Feedback for Physically Variant Components
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Solution Overview
Problem
Traditional ultrasonic welding methods fail to accurately weld physically variant workpieces due to inconsistent energy directors and material variations, leading to inefficiencies and errors from frequent recalibration needs.
Innovation Solution
Implementing a method that monitors weld force or force rate of change with sensors to determine when to end the weld phase, allowing for consistent welding across workpieces with different shapes and sizes by setting predetermined levels based on sensed parameters, eliminating the need for frequent recalibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional ultrasonic welding methods use predetermined time or distance parameters to end the weld phase, then the welding process is simple to control, but the welding accuracy deteriorates when workpieces have physical variations in energy director size and shape
Solution Approach 1:
The patent implements feedback control by using sensors to monitor weld force or force rate of change in real-time during the welding process. The system continuously measures the actual weld force and compares it against predetermined threshold levels, automatically adjusting or terminating the weld phase based on the sensed parameters. This feedback mechanism enables accurate welding of physically variant workpieces without requiring complex recalibration, as the system adapts to each workpiece's actual characteristics during the welding process itself.
2Reliability
If traditional methods use fixed weld phase duration based on elapsed time or press position, then the process is efficient and quick, but the reliability deteriorates when energy directors vary in height, width, volume, and shape
Solution Approach 1:
The welding system performs self-calibration and self-adjustment by automatically sensing the actual weld force characteristics of each workpiece and adapting the weld phase termination criteria accordingly. The sensors detect the force rate of change or force level specific to each energy director configuration, and the control system autonomously determines the appropriate weld phase duration without requiring external intervention or manual recalibration. This self-service capability ensures consistent welding reliability across physically variant workpieces while eliminating time-consuming recalibration operations.
3Manufacturing precision
If the weld phase ends based on predetermined distance traversed from start of weld, then the control is simple, but the manufacturing precision deteriorates for workpieces with different energy director dimensions
Solution Approach 1:
The patent replaces traditional mechanical position-based control with a sensor-based force measurement system. Instead of relying on mechanical displacement sensors or position encoders to determine weld phase termination, the system uses force sensors to directly measure the weld force or force rate of change. This substitution of mechanical position control with force-based sensing provides more accurate detection of weld completion, as force directly reflects the actual welding process state rather than just the position of moving parts. The control system remains relatively simple by using predetermined force threshold levels, maintaining ease of operation while achieving high manufacturing precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures accurate and efficient welding of physically variant workpieces with higher tolerance and lower error rates, achieving consistent results by ensuring full contact between abutting surfaces regardless of geometric or material variations.
Implementation Method 1
initiating a weld phase by outputting energy from the ultrasonic welding stack to the first workpiece
Implementation Method 2
presses for use in ultrasonic welding or other systems for vibratory joining of plastic parts
Data Source
AI summary
The present disclosure can provide for an ultrasonic welding method for a pair of workpieces. The method can include first pressing an ultrasonic welding stack against a first workpiece in the pair so that the first workpiece comes into contact with a second workpiece in the pair. The method can then provide for initiating a weld phase by outputting energy from the ultrasonic welding stack to the first workpiece. The method can provide for monitoring, with at least one sensor, a sensed parameter. The sensed parameter can be, for example, weld force and/or weld force rate of change. The method can provide for determining whether the sensed parameter has reached a predetermined level. Based on determining that the sensed parameter has reached the predetermined level, the method can provide for ending the weld phase.